This invention relates generally to pneumatic paintball guns (“markers”) and their operating components. In the sport of paintball, it is generally desirable to have a marker that is as small and light as possible. Smaller and lighter markers increase a players' mobility. Players benefit from increased mobility by being able to move more quickly from bunker to bunker, making it easier to avoid being hit. Further, in the sport of paintball, the marker is treated as an extension of the body such that a hit to the marker counts as a hit to the player. It is desirable, therefore, to have a paintball gun with as small a profile as possible while substantially maintaining or improving performance characteristics of the marker, such as firing rate and accuracy.